18 



FORM AND HABIT: TUE WING. 



tatus). The young of this bird have well-developed claws 

 on the thunil) and first finger, and long before they can 

 flv they nse them as aids in clambering about the Ijushes, 

 very nuieh as we may imagine the Archieopteryx did. 

 In tlie adult these claws are wanting. 



Some eminently aquatic birds, as Greljes and Pen- 

 guins, when on land, may use their wings as fore legs in 

 scraml)ling awkwardly along ; while some flightless birds, 

 for example, the Osti'ich, spread their wings when run- 

 ning. 



But let us consider the wing in its true ofliee, that of 

 an organ of flight, showing its range of variation, and 



finally its degradation into 

 a flightless organ. Among 

 flying birds the spread 

 wiiiffs measure in extent 

 from about three inches in 

 the smallest Hummingbird 

 to twelve or fourteen feet 

 in the Wandering Albatross. The relation between 

 shape of wing and style of flight is so close that if you 

 show an ornithologist a bird's wing he can generally 

 tell you the character of its owner's flight. The ex- 

 tremes are shown by the short-winged ground birds. 



Fia. 5. — Short, rounded winfr and large 

 foot of Little Black Kail, a terres- 

 trial l-iird. (Vj natural size.) 



FiQ. 6.— Long, pointed wing and small foot of Tree Swallow, an aerial bird. 

 (3/5 natural size.) 



such as liail, Quail, Grouse, certain Sparrows, etc., and 

 long- winged birds, like the Swallows and Albatrosses. 

 There is here a close and, for the ground-inhabiting 



